Trail builder attachment for tractors



Mrch 3, 1942. F; P. QL'AVQVLER TRAIL BUILDER ATTACHMENT FOR TRACTORS I F iIed AugQ M, 19:59 7 Sheets-Sheet 1 FQA'NKPLAWL 19, 11v VENTOR,

A TTORNEY March 3, 1942, A F. P. LAWLER TRAIL BU'ILDER ATTACHMENT FOR TRACTORS '7 Sheets-Sheet '5 Filed Aug. 14, 1939 March 3,1942. F. P. LAWLER 7 TRAIL BUILDER ATTACHMENT FOR TRACTORS Filed Aug. 14, 1939 7 Sheet-Sheet 4 I INVENTOR.

A TTORNE Y March 3, 1942. F. P. LAWLER TRAIL BUILDER ATTACHMENT FOR TRA CTORS Filed Aug. 14, 1939' 7 Sheets-Sheet 5 INVENTOR.

A TTORNEY March 3, 1 942. F, P, L W ER 2,274,904

TRAIL BUILDER ATTACHMENT FOR TRACTORS Filed Aug. 14, 1939 7 Sheets-Sheet 6 /-Tz4/v/ PL A w. 50, V IN VEN T OR.

. ATTORNEY March 3, 1942. W R

' TRAIL BUILDER ATTACHMENT FOR TRAcToRs,

Filed Aug. 14, 19:59 '7 Sheets-Shet 7 A .M II\ WIIIIIIIIIZZIIZI-III fZZA/YK P LA wL/52/ INVENTOR.

A TTORNEY Patented Mar. 3, 1942' TRAIL BUILDER ATTACHMENT FOR TBACTORS Frank P. Lawler, Huntington Park, calm, assignor, by mesne assignments, to The Buckeye Traction DitcherCompany, Findlay, Ohio Application August 14, 1939, Serial No. 290,094

19 (Cl. 37-1d4) My invention relates to earth moving devices of the type having -a tool or blade carried by a vehicle so as to be brought into engagement with the earth material while the vehicle is propelled, and relates in particular to a simple and rugged attachment which may be readily applied to tractors.

In the preferred form of the device, a pusher blade is secured in operative position at the front end of the tractor so as to serve as a means for Pushing a body of earth material ahead of the tractor or to serve as a scraper to scrape on a portion of the ground ahead of the tractor. It is found that in the use of tractors with many devices of this character, full pushing efllciency of the tractor is not attained for the reason that the addition of the ground working equipment to the tractor produces a structure having a center of gravity near the front ends of the tractor treads, with a result that excessive wear is imposed on the front rollers or bearings for the chain tread.-'

It is an object of the present invention to provide a tractor with ground working means pro- Jecting forwardly from the tractor, such ground working means being so proportioned and positioned that the resulting structure of tractor and attachment has a center of gravity shifted but little forward of the central transverse plane of the tractor tread elements. This relieves the front ends of the tread structures from excessive wear, and makes possible the obtaining of maximum pushing force by the tractor for the reason that the tread chains maintain maximum engagement with the surface of the ground.

It is a further object of the invention to have the pusher blade or mold board of the tractor Y attachment adjustably mounted by means of a universal joint so that this pusher blade 'may have a variety of positions of adjustment, and

the same rigidly in the desired, position of adjustment.

It is a further object of the invention to provide an earth working attachment for a tractor having a thrust member secured to the tractor er member from the front of the tractor is maintained at a minimum.

It is a further object of the invention to provide in the means for rigidly securing the pusher blade in its desired position of adjustment, a'clamping it is a'further object of the invention to provide a device of this character having simple means for rigidly securing the pusher blade in any of its positions of adjustment.

from a position in a horizontal plane to a po h tion pitched relative to the horizontal plane, with supporting means for the pusher blade tohold means which may be readily applied and which will rigidly clamp the cooperating parts of the attachment. This clamping means employs a clamping screw having an enlarged tapered head to tightly engage atapered seat formed in one of the parts to be secured together, this engagement of the head with the seat not only tightly clamping the parts together, but also cooperating as a centralizing or positioning means for bringing the cooperating parts into their respective positions of operation in response to the engagement of the tapered head with the tanered seat.

It is a further object of theinvention to provide a ground working attachment for a tractor having supports mounted on the tread elements of the tractor so as to move up and down with these tread elements as the tread elements ad justthemselves to the surface contour of the ground over which the tractor is being driven,

and equalized lifting means mounted on the supporting members, to accomplish raising and low- 1 ering of the ground engaging element of the attachment, and to provide in conjunction with the equalized lifting means an equalizing attachment of sensitive or fast acting character to connect the lifting means to the supporting part of the attachment which carries the ground engaging member represented by the pusher blade. his

tion taken as indicated by the line control means or cable control means for the other, without the necessity of changing the thrust member, pusher blade or supports which the chain belt :2 of thetread elements 2|. As a tractor of this type is propelled over uneven ground, the forward portions of the tread eleare secured to the tread elements of the tractor so as to transmit the dead weight of the attachmen directly to the tread element.

It is a further object of the invention to provide a simple and rugged hydraulic lift means for each of the supports. which hydraulic lift I means are detachably secured tothe supports Fig. 1. w

' Fig. 3 is a side elevation showing the attachment in raised position.

Fig. 4 is an enlarged cross-sectional view taken substantially as indicated by line 5-4 of Fig. 1,

so that some parts are shown partly sectioned and others are shown in elevation.

. 'tions of the tread elements 2|.

Fig. 5 is a plan view showing a form of my in- I vehtion wherein a cable is employed in the con- Fig. 6 is a side elevation of thedevice shown in Fig. 5, but with the pusher blade in' angled position.

Fig. 7 is a side elevation similar to Fig. 6, but

showing the pusher blade raised.

Fig. 8 is an enlarged fragmentary cross-section taken as indicated by the line 8-8 of Fig.1.

' the plane indicated by the line 10-! a 6: Fig. 1.

30 trol means for raising and lowering the working elements.

Fig. 11 is an enlarged cross-section taken on the plane indicated by the line ll--ll of Fig. 5.

Fig. 12 is an enlarged fragmentary cross-secl2--|2 of P18.

Fig. 13 is an enlarged fragmentary section taken as indicated by the line l3l3 of Fig. 5. I Fig. 14 is a fragmentary plan view to reduced scale showing the simple manner of applying the equalizing means. to a standard bulldozer.

Fig. 15 is an enlarged fragmentary perspective view of the front end portion of one of the thrust member extensions and associated parts.

Reference is hereby made to my co-pending application Serial No. 290,093 in which certain of the subject matter shown herein is claimed.

In the practice of my invention I prefer to em- Q ploy a tractor of the caterpillar or track laying type, such as shown in Figs. 1 to 7 of the drawings. This tractor 20 has at the sides thereof .tread elements 2|, each comprising a chain belt 22 in the form of a horizontally elongated loop and means for supporting and driving-the Such tractors have an engine 25a disposed forwardly thereon, with suitable transmission to deliver driving power through the sprockets 23 to ments 2| swing vertically on the. axes defined by the sprockets 33.

Fig. 1, to a lateral, or bulldozer position, as shown in Fig. 5.

The thrust member 2'! comprises a pair of hollow side arms 23, which extend'along the sides of the tractor 33, and a cross-member 3|! rigidly secured to the front ends of the side arms 29 in position to extend across the front of the tractor at a minimum distance from the front end of the tractor., The cross-member 30 has a central portion 3| and a pair of rearwardly sloping portions 33, all of which are preferably of hollowcrosssection. The 'side arms 29 are of such length that the rear ends thereof may be connected by means of fittings 33 to pivots 34 consisting of pins which project outwardly from the rearwardpor- As shown in Fig. 2, the fittings '33 have rearwardly faced notches 35 therein, to receive the pins 35, the rear ends of the notches 35 being closed by blocks 35 which are secured in position by vertical pins 31. The

thrust member 31. and the parts securedthereto, may be readily detached from the tractor 23 by lifting the pins 31 and removing the blocks, which will permit movement of the thrust member 21 inforward direction to carry the fittings 53 outof engagement with the pivot pins or trunnions 34. The thrust member 2'! may be readily mounted on the tractor by a reversal of the foregoing procedure.

The pusher blade", sometimes referred to as the mold board, is of such characterthat as it is moved forward in the lowered position in which it is shown in Fig. 2, it will roll ahead of it the earth material which is being moved. As best shown in Figs. 1 and 9, the pusher blade 28 in-- cludes a curved plate 38 which is welded to and extends upwardly from a backing plate 39, the lower portion of which carries a replaceable knife Mi and replaceable corner bits! of chilled steel.

The upper edge portion of the plate 38 is bent .rearwardly to form a horizontal flange 42 and a horizontal bottom plate 43 is projected rearblade 35 to the central portion 3| of the thrust member 21. Such "universal joint 45 comprises a horizontal pin 41 which extends through the central portion 3! ofthe cross-member 30 and has ahead 48 of furcatedv form, with aligned openings 43 to receive a substantially vertical pin whichis passed through openings 5| in spaced plates 52 and 53, which project rearwardly from the plate 33 above the bottom plate 43, as shown in Figs. 2 and 3. Vertical bracing plates 54 are 2,274,904 vertically spaced a greater distance apart than are the central portions thereof. As shown in Figs. 2, 3, and 9, adjustable means 58 are provided for connecting the forward ends of members 10 to the end'portions of the pusher blade 28. The plates 52 and 53 form channels 51 in the back of the pusher blade 28, which channels 51 increase in vertical dimension from the center of the pusher blade toward the ends thereof, and in the ends of these channelsi'l essentially vertically disposed arcuate walls 81 are secured.

The walls each have a plurality of openings 62 spaced vertically through which openings a bolt 63 may be selectively passed to clamp a connector body 54 to the wall 6|. Theconnector body 64 is shown as a block having horizontally projecting walls 66 through which a pivot pin 61 11, each extension 10 comprises a channel bent from sheet steel so as to fit over a side arm 29. The channel forming the extension 18 has the top and bottom walls thereof stifiened by vertically projecting flanges H. The invention provides a simple means for clamping the extension arms'29. The. inventidn employs two diflerent forms of this clamping means, as shown at 12 and 13 in Fig. 5. The clamping means I2 are vertically disposed; whereas, the clamping means 13 are horizontally disposed. As shown in Figs. 10, and 11; each of these clamping means 12 and 13 employs a screw It, so that such screws 14 may be used interchangeably. Each screw l6 operating parts of the clamping means 13, a collar or body 82 is secured against the outer end of the sleeve 89 by means of a clamping screw l4. The extension 10 is then placed in intermediate position, as shown in Fig. 5, with the collar 92 projecting through an opening 90 in the side wall'thereof, and the securing weld 9| is applied.

.A feature of the invention is that each extension 18 is rigidly securedto its cooperating side 'arm 29 by a pair of securing means. When the pusher blade 28 is in lateral, or bulldozing position, as shown in Fig. 5, securing means 12 and I3 are employed in spaced relation. pusher blade 28 is in this laterally extended position, the extensions 70 diverge so that when the rear end of each extension 10 lies close to a side arm 29,"the intermediate portion of the extension 10 will be spaced from the side arm, but will be rigidly connected to the forward portion of the side arm by means of the sleeve 89 and its cooperating clamping screw 14, as shown in Fig. 11. Each side arm 29 has only one sleeve 89, but has in the top face thereof. four openings 81 as indicated at 81a, 87b, 81c, and 81d in Figs.

'1 and 5, each of these openings 81 leading into a threaded body Not the character shown in Fig. 10. Each extension 19 has three of the collars 82 mounted in the upper wall thereof, as indicated at 92a, 92b, and 820: When the pusher I0 in desired positions of adjustment on the side c has a head I5 with a downwardly converging conical face 18 coaxial with a. cylindrical barrel 1! and a threaded stem 79. The clamping means ing fit with the barrel TI of the screw it, and the threaded bore 8| being adapted to receive the threaded stem 18. A wall or body 82 is welded int-o an opening 89 in the upper wall 84 of the channel forming the extension 10, this wall 82 having a conical seat 85 to cooperatewith the face '16 of the head 15. The openingBS through the-body 82 is larger than the opening 81 in the top of the side arms 29, which opening 91 communicates and is coaxial with the bore 80-of the threaded body 79.

One of the features of this clamping means 12 is that the'alignment of the cooperating parts may be readily obtained. 'Forexamplewith the threaded body 19 in place in the side arm 29, the

body 82 may be placed on the upper surface of the side arm 29, and theclamping screw It may be screwed tightly into place. The extension 10, with the opening 86 therein slightly oversize, may

be'placed in position, as shown in Figi 10, and the blade 28 is in bulldozing position, as shown in Fig. 5, screws I4 are passed through the collars 82 in the sides of the extensions 19 into the 'sleeve 89, and a screw 15 is passed through the collar am at the rear' end of each extension 10 P into an opening 87b in the cooperating side arm 29. When the pusher blade 28 is in either of its angled positions, asshown in Fig.1, screws 14 will be passed through collars 82a and 8211 into openings 81c and 81d, and in the other extension lo screws '14 will be passed through the collars 82a and 820 into openings 87a and 81d. In each instance the extensions ill will be rigidly secured by pairs of clamping screws.

For the support of the front end of the thrust member 27 and its pusher blade 28, I provide supporting members 92 mounted on the tread elements 2| so as to transmit the load of the forward portion of the attachment directly to the tread elements and thence to the ground, without placing strains on the body castings of the tractor 20. It is a feature of the invention that different types of lift means may be selectively employed with the thrust member 21, pusher blade '28, and supports 92. Towards this end the supporting members 92 each have a post structure 93, the lower portion of which is bolted, as at 94, to the internal'supporting structure 25 of a tread element. At the upper end of each post 93 there is a horiontal portion or member 95,

preferably made from a channel with its flanges elusive.

The horizontal portion 95 of each post 93 has front attachment means comprising a pair of spaced fins or lugs 99, and rear attachmentmeanscomprising a pair of upwardly extending fins I00, these fins .99 and Hill being respectively drilled to receive horizontal pins llll and I02. In the use of the hydraulic type of lift means 91,

shown in Figs. 1 to 4, the front pins I0l support When the I and the pins I02 support bellcrank members I each comprised of laterally spaced plates I00 and I00 bridged by a plate I01 which is welded in 1 place, Each pair of plates I00 and I00 straddles a power cylinder I00, and such plates vare cut so as to form a relatively long, forwardly extending swing on the pivot represented by the pin I02.

The front end of each long lever I00 carries a transverse pin II2 from which a connecting rod IIO extends downwardly. Each connecting rod IIO has pivot means I I4 at its lower end for connection to an end of an equalizer IIO which is mounted on the rearwardportion of the upper face of the cross-member 00. As best shown in Fig. 4, the equalizer IIO comprises a central link I I6, fulcrumed at its center by means of a pin I I1", supported by webs -I I0 which project upwardly from the central portion 0I of the cross-member 30. The ends H9 or the member IIO are bent rearwardly at a relatively small angle, and pins I supported therein are connected by means of links I2I with pins I22 carried at the inner ends I20 of outer levers I24 which are fulcrumed on pins I20 carried by fins I2 0,,which project upwardly from the rearwardly sloping portions 02 of the cross-member 00. The pins I20 are positioned near the' inner ends I20 of the levers I,

so that the outer e'nds I21 of the levers I20 will rotation than will the inner ends I20 thereof. As also shown in Fig. 4, the outer end I21 of eacli swing to a greater distance for a given are of lever m has a ball m m unted thereon to form part of a pivotal connectio Hi4, the cooperating portion of which comprises a split socket I29 connected to the lower end of the connecting rod. 1

The lift means provided by the invention has slow acting equalizing'means represented by the,

power cylinders I00, and fast acting, sensitive equalizing means consisting of theequalizer H0.

As shown'in Fig. 4, the fluid inlets I00'to' the cylinders I03 are'connected through conduits IOI with a fluid pressure line I02, and the outlets I00 oi the power cylinders I00 are connected to conduits I80 with a fluid line I05, the ducts I02 and I30 being connected with a suitable valve and source of fluid and reservoir, not shown for the reason that the same may be in accordance with standard hydraulic practice. Owing to the fact that the cylinders I08 are interconnected,= there' may be an"equalizing flow of fluid therebetween.

. the front ends of double acting power cylinders,

pins III and I02 pass through the lower portions or the plates I00, thereby securing the same rigidly, to the table portions 00 of the supporting members 02. Across the forward portion of eada pair of plates I00, a shaft or bolt I00 is extended. On one of these bolts I00, as shown in Figs. 0 and 7, a sheave I00 is mounted, and from a casing I00 which surrounds this sheave I00 and is pivoted on the shaft I00, a cable tube IOI extends rearwardly to a sheave casing I42 which is piv-' otally mounted at the outer end of an arm I00 extending laterally from a cable winch I00, preferably mounted at the rear end of a tractor. From the cable drumI00 of this winch I00, as

shown in Fig. 5. a cable I40 is carried around a sheave I01 supported in th'ecasing I42 into the tube I through. which it is carried to the sheave I00. The cable extends over the sheave I00 and a portion I00 thereof drops down .to a sheave 'I00 supported'by means of a fitting I00 at the outer end I21a or a lever I24a forming a part of an equalizer IIOa which is in all respects the same as the equalizer III-shown in Fig. 4, with the exception that the outer ends of the outer levers of such equalizer areprepared for securement of the sheave mounting I00 instead of the ball and socket Joint IIO employed in conjunction with the hydraulic lift means 01. The cable is extended under the sheave I40 and a portion III thereof, as shown in Figs. 6 and '1, is carried up from the sh'eave I00 to a sheave I02, supported at an end of a spreader or connecting tube I00, whichextends from the upper end of one arm I01 to the upper end of the other arm I01. This tube I00 is swivelly connected to the upper ends of the arms I01 by means of ball and socket type joints I00; As shown in Fig. 12, each-joint I04 comprises a ball member I00 which is secured to an end of the tube I00,-and a split socket I00 secured to the upper end of each of the cooperating arms I01. The tube I00 supports two of the sheaves I02 near the ends thereof to support a that the upper portion of each sheave I02 will project into an opening I00. in the lower part of the tube I00, so that the lateral extension I01 of the cable will lie within the tube I00. From the second of the sheaves I02 a portion I00 of the cable extends down to a sheave IOI which is a counterpart of the sheave I20. This cableexas the supports 02 are raised and lowered due to. v

the travel of the tread element '2I over uneven ground. This equalizing action will be relatively slow, but the compensation of vthe equalizer IIO f for changes in relative positionsof th'e tr elements 2i will be substantially instantaneous,' and the weight of the pusher member 00 and the blade 28 will be always substantially equally distributed between the two supporting members 92. As shown in Figs. 5, 6, and 7, the cable type lift means 98 may be readily substituted for the hytends under this sheave IOI and a portion of the cable I62 is carried up to the bolt I00 at the far side of the tractor or opposite from the bolt I00 on which the sheave I00 is mounted. .The downwardly hanging cable loop formed in part by the cable portions I00-IOI and I00I02 cooperate with the laterally extending portions of thecable Y to form a primary equalizing means to compensate for vertical movement of the tread elements These cable loops however are connected through the sheaves I00 and IOI with the opposite ends of the secondary, sensitive equalizing means 0a capable of giving an equalization or I compensation within a small range of movement, which is relatively instantaneous, the result-being that the load of the thrust member 21 and the pusher blade at is evenly divided between the supports 02 independently mounted on the tread I gravity of the tractor is ordinarily substantially intermediate the ends of the tread elements 2|. The line B-B of Fig. 2 passes through the center of gravity of the earth working device consisting of the tractor and my attachment which is so designed that the center of gravity or center of pressure of the tractor tread relative to the ground is not shifted forwardly a great distance from the line A-A as the result of the adding of the attachment to the tractor. It will be noted that the pusher blade 28 is disposed at a minimum distance from the front end of the tractor 20. In order to keep this distance at a minimum, I have provided for a'telescoping of the plates 52 and 53 over a sloping side portion which are connected directlyto the end portions of the mold board I90, thereby avoiding the use II of a separate cross-member such as the membe 30, shown in Fig. 1.

I have herein disclosed a simple and practical form of my invention, but it .is recognized that various parts or elements thereof may be replaced by other par 5 or elements of equivalent 32 of the front member 30 when the pusher blade 28 is in angled position, as shown at a in Fig. 1. In view of the fact that the plates 52 and 53 diverge from the central portion of the pusher blade, the forward portion of the front member 30 may enter one of the channels 5! whenever the pusher blade 28 is swung into angled position, and even though the blade may be at the same time pitched relative to horizontal by the moving of the blocks or connector bodies 84 into different equalizer II5 does not take up space so as to increase the spacing of the pusher blade 28 from the front end of the tractor, for the reason that this equalizer, H5 is mounted on the rearward portion of the upper face of the cross-member 30. The support of the pusher blade 28, in all of its positions, is rigid for the reason that the extensions III are rigidly clamped to the side arms 29 and the connector bodies 64 are rigidly clamped on the'segments 58 which are welded in place on the back of the pusher blade 28.

It has been explained how the equalizer is constructed so as to make it possible to set the cross-member 30 of the tractor attachment rela changing the center of gravity of the tractor treads relative to the ground. An additional feature of the equalizer construction is that the ends.

of the equalizer II5 bend back so that the ends of the arms I24 lie substantially under the for- I the sides thereof, the combination of a ground engaging member; means for connecting said ground engaging member to said tractor so that it may be. raised and lowered; equalizing means carried by said treadelements and being operative to apply a force to lift said ground engaging member; and sensitive equalizing means connecting said first named equalizing means to said positions along the segments 58. The sensitive ground engaging member, said equalizing means compensating for the movement of said tread elements relative to said ground engaging member as said tread elements move over uneven 3 ground.

the sides thereof, the combination of: a ground engaging member; means for connecting said ground engaging member to said tractor so that it may be raised and lowered; and supporting means for said ground engaging member con-' nected to both of said tread elements so that the weight of said ground engaging member will be 40 substantially equally-divided between said tread tively close to the front end of the tractor so that elements, said supporting means comprising a slowacting hydraulic equalizing means and a.

fast acting mechanical equalizing means connected in the parallel.

3. In an attachment for use with a tractor of the character described having tread elements. at the sides thereof,'the combination of a ground engaging member; means for connecting said ground engaging member to said tractor so that ward ends of the lift means formed in part by the .50 it may e r ised and lowered; and suppor in levers I04. The equalizer H5 is bent around the radiator of the. tractor so that the ends of the levers I24 lie behindthe verticalplane defined by the front face of the tractor radiator. Accordingly, the length of the levers I04 is minimized, and the opposite extremities of the equalizer II5 are disposed in such position that they will clear the pusher member 28 when the same is swung into angled position, as shown'in Fig. 1.

It will be understood that in many uses of the invention the cross-member 30 and the pusher member 28 may be rigidly secured together or formed as one part, as in bulldozers wherein the side arms of the bulldozer attachment are connected directly to the mold board and extend rearwardly therefrom. In Fig. 14 I show the sensitive equalizer H5 as a means for connecting the mold board I90 of a bulldozer, attachment l9l to lift members I92 which may be levers such as the levers I04 of a hydraulic lift means. The equalizer H5 is secured to a lateral plate I93 forming part of the mold board I90 and the levers I24 of the equalizer II5 bend rearward so as to encompass the radiator I 05 at the front of the tractor. The mold board I90 is connected. to 75 en g member Will substantially equally I means for said ground engaging member connected to both of said tread elements so that the weight of said ground engaging member will be substantially equally divided between said tread elements, said supporting means comprising a slow acting equalizing means and a fast acting mechanical equalizing means connected in the parallel-said last named equalizing means comprising a central lever fulcrumed on said ground engaging member, outer levers fulcrumed on said ground engaging member, means providing a pivotal connection between the inner ends of said outer levers and said central lever, and means connecting the outer-ends of said outer levers to .65 said first named equalizing means,

round engaging member to said tractor so that it may be raised and lowered; a lift means on each side of said tractor; and equalizing means connecting said lift means to said ground engaging member so that the weight of said ground outer ends of said outer levers and said lift means.

5. In an attachment for use with a tractor of the character described having tread elements at the sides thereof, the combination of: a ground engaging member: means for connecting said ground engaging member to said tractor so that it may be raised and lowered; a liftmeam on each side of said tractor; and equalizing means connecting said lift means to said ground engaging member so that the weight of said ground engaging member will be substantially equally divided between said lift means, said equalizing means co'mprisinga central lever fulcrumed on said ground engaging member, outer levers fulcrumed on said ground engaging member, means providing a pivotal connection between the inner ends of said outer levers and said central lever, and means connecting the outer ends of said outer levers to said lift means.

6. In an attachment for use with a tractor of the character described having tread elements at the sides thereof, the combination of a thrust member comprising a pair of side-arms to extend along thesides of the tractor and a crossmember connected to the front portions of said side arms in position to extend across the front of the tractor; a pusher blade secured to the forward portion of said thrust member; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves along; cable means for lifting said pusher blade and said thrust member, mounted on said supporting members so as to have a portion of the cable lift means extending downward from each of said supporting members; a pair of levers fulcrumed on said thrust members; an equalizing element connecting one end of one of said levers to one end of the other of said levers: and means connecting the remaining ends of said levers respectively to said downwardly extending portions of said cable lift means.

7. In an attachment for use with a tractor of the character described having tread elements at the sides thereof, the combination of a thrust member comprising a pair of side arms to extend along the sides of the tractor and a cross-member connected to the frontportions of said side arms in position to extend across the front .of the tractor: a pusher blade secured to the forward portion of said thrust member; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves along; cable means for lifting said pusher blade and said thrust -member,

mounted on said supporting. members so as'to' have a portion'of the cable lift means extending downward from each of said supporting members: a centrally pivoted lever mounted on the central portion of the cross-member: outer levers fulcrumed on said thrust member adjacent the ends of said centrally pivoted lever: means connecting the inner end of each of said outer levers divided between said lift means, said equalizing means comprising a central lever fulcrumed on lever so that movement of one of said outer levers will cause a movement of the other of said outer levers in the opposite direction; and means for connecting the outer ends of said outer levers. respectively to said downwardly extending 'pori tions of said cable lift means.

8. In an attachment of the character de scribed for use with a tractor having tread elements at the sides thereof, the combination of a thrust member carrying ground engaging means supported so as to have vertical movement relative to the tractor, said thrust member having a cross-member which extends across the front end of the tractor; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves along; cable lift means for said thrust members supported in part by each of said supporting members and having a portion extending downwardly from each of said supporting members a pair of levers fulcrumed on said thrust member; an equalizing element connecting one end of one of said levers to one end of the other of said levers; and means connecting the remaining ends of said levers respectively to said downwardly extending portions of said cable lift means.

9. In an attachment of the character described for use with a tractor having tread elements at the sides thereoLthe combination of a thrust member carrying ground engaging means supported so as to have vertical movement relative to the tractor, said thrust member having a cross-member which extends across the front end of the tractor; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as'thetractor moves along; cable lift means for said thrust members supported in part by each of said supporting members and having a portion extending downwardly from each of said-supporting members; a centrally pivoted lever mounted on the central portion of the cross-member; outer;

levers fulcrumed on said thrust member adjacent the ends of said centrally pivoted lever; means 'solstotransmittosaidthrustmemberthmughconnecting the inner end of each of said outer levers to the adjacent end of said centrally pivoted lever so that movement of one of said outer levers will cause a movement of the other of said outer levers in the opposite direction; and means for connecting the outer ends of said outer levers respectively to said downwardly extending portions of said cable lift means.

'10. In an attachment for use with a tractor of the character described, having tread elements at the sides thereof, the combination of a thrust member, carrying a ground engaging member. supported on the tractor so as to have rising and lowering movement relative to the said equalizing means movement to raise said thrust member.

to the dissent end of said centrally pivoted-76 11.111 an .W t (or me with 1mm:

2,274,904 i of the character described, having tread elements at the sides thereof, the combination of a thrust member, carrying a ground engaging member, supported on the tractor so as to have rising and lowering movement relative to the tractor; a supporting member mounted on eachof said tread elements of the tractor so as to rise and fall therewith as the tractor moves over uneven ground; cable actuating means mounted on said tractor; a cable extending from said cable actuating means to one of said supporting members; means to guide the cable across the tractor to the other of said supporting members; guide means whereby said cable is formed into-loops extending down from each of said supporting members; spreader means flexibly connected between said supporting members, one of the functions of said spreader means being to resist the force of tenshion acting in the portion of said cable which extends across from one of said supporting members-to the other; and means connecting said loops of saidcable to said thrust member so that the actuation of said cable by said actuating means will accomplish movement of said thrust member.

12. In an attachment for use with a tractor of the character described, having tread elements at the sides thereof, the combination of a thrust member, carrying a ground engaging member, supported on the tractor so as to have rising and lowering movement relative to the tractor; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves over uneven ground; cable actuating means mounted on said tractor; a cable extending from said cable actuating means to one of said supporting members; means to guide the cable across the tractor to the other of said supporting members; guide means whereby said cable is formed into loops extending down from each of said supporting members; spreader means flexibly connected between said supporting members; one of the functions of said spreader means being to resist the force of tension acting in the portion of said cable which extends across from one of said supporting members to the other; and independent equalizing means mounted on said thrust member, said equalizing means connecting said loops of said cable to said thrust member so that the actuation of said cable by said actuating means gill accomplish movement of said thrust mem- 13. In an attachment for use with a tractor of the character described, having tread elements at the sides thereof, the combination of a thrust member, carrying a ground engaging member, supported on the tractor so as to have rising and lowering movement relative to the tractor; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves over uneven ground; cable actuating means mounted on said tractor; a cable extending from said cable actuating means to one of said supporting members; means to guide the cable across the tractor to the other of said supporting members; guide means whereby said cable is formed into loops equalizing means connecting said loops of said cable to said thrust member so that the actua tion of said cable by said actuating means will accomplish movement of said thrust member, said equalizing means being ofrelatively sensitive character and compensating for the sudden changes in position of said treads and said supporting members mounted thereon.

a 14. In an attachment for use with a tractor of the character described, having tread elements at the sides thereof, the combination of a thrust member, carrying a ground engaging member,

supported on the tractor so as to have rising and ,lowering movement relative to the tractor; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves over uneven ground; cable actuating means mounted on said tractor; a cable extending from said cable actuating means to one of saidsupporting members; means to guide the cable across the tractor to the other of said supporting members; guide means whereby said cable is formed into loops extend-v ing down from each of said supporting members; spreader means flexibly connected between said supporting members, meet the functions of said spreader means being to resist the force of tension acting in the portion of said cable which extends across from one of said supporting members to the other; and independent equalizing means connecting said loops of said cable to said thrust member so that the actuation of said cable by said actuating means will accomplish movement of said thrust member, saidequalizing means comprising a pair of levers pivotally mounted on said thrust member, an equalizing connection between said levers whereby movement of one of said levers in one direction will result in movement of the other of said levers in the opposite direction, and means connecting said levers respectively to said loops.

15. In an attachment for use with a tractor of the character described, having tread elements at the sides thereof, the combinationof a thrust member, carrying a ground engaging member, supported on the tractor so as to have rising and lowering movement relative to the tractor; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith as the tractor moves over uneven ground; cable actuating means mounted on said tractor; a cable extending from said cable actuextending down from each of said supporting f members; spreader means flexibly connected between said supporting members, one of the functions of said spreader means being to resist the force of tension acting in the portion of said cable which extends across from one of said supporting members to the other; andindependent ating means to one of said supporting members; means to guide the cable across the tractor to the other of said supporting members; guide means whereby said cable is formed into loops extending down from each of said supporting members; spreader meanshaving the endsthereof flexibly connected to said supporting members, said spreader means comprising a tube with laterally directed openings near the ends thereof, the interior of said tube forming a path for a portion of said cable and there being sheaves secured to said spreader means in position to guide the cable through said openings; and means connecting said loops of said cabl to said thrust member so that the actuation of said cable by said actuating means will accomplish movement of said thrust member.

16. In an attachment for a tractor of the character described having tread elements at the sides thereof which rise and wall as the tractor moves over uneven ground, the combination of a ground engaging member connected to the tractor so as to have movement in a vertical plane;

a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith; cable actuating means; a cable extending from said cable actuating means to the first of said supporting members; a guide for said cable carried by said first supporting members so that said cable maybe extended downward so asto'form a first cable loop; spreader means extending over said tractor from one of said supporting members to the other, the ends of said spreader means being flexibly-connected to said supporting members; a sheave disposed adjacent oneend of said spreader member to receive the cable from said first loop; a second sheave disposed adjacent the other end of said spreader member to receive the cable from said first named sheave; cabie engaging means secured by the second of said supporting members, saidcable forming a second loop extending downwardly between said second sheave and said cable engaging means; and means carried by said ground engaging member to engage said loops so that the shortening of said loops will raise said ground engaging member.

'17. In an attachment for a tractor of the character described having tread elements at the sides thereof which rise and fall as the tractor moves over uneven ground, the combination of a ground engaging member connected to the tractor so as to have movement in a vertical plane; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith; cable actuating means; a cable extending from said cable actuating means to the first of said supporting members; a guide for said cable carried by said first supporting member so that said cable may be extended downward so as to form a first cable loop; spreader means extending over said tractor from one of said support-' ing members to the other, the ends of said spreader means being flexibly connected to said supporting members; a sheave disposed adjacent one end ofsaid spreader member to receive the cable from said first loop; a second sheave disposed adjacent the other end of said-spreader member to receive the cable from said first named sheave; cable engaging means secured by the second of said supporting members, said cable forming a second loop extending downwardly between said second sheave and said cable engaging means; and equalizing means connecting said loops to said ground engaging member.

18. In an attachment fora tractor of the character described having tread elements at the sides thereof which rise and tall as the tractor moves over uneven ground, the combination of a ground engaging member connected to the tractor so as to have movement in a vertical plane; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith; cable actuating means;-a cable extending from said cable actuating means to the first of said supporting members; a guide for said cable carried by said first supporting member so that said cable may be extended downward so as to form a first cable loop; spreader means extending over said tractor from one of said supporting members to the other, the ends of said spreader means being flexibly connected to said supporting members, and said spreader member shortening of said loops will raise said ground engaging member.

19. In an attachment for a tractor of the character described having tread elements at the sides thereof which rise and fall as the tractor moves over uneven ground, the combination of a ground engaging member connected to the tra'ctor so as to have movement in a vertical plane; a supporting member mounted on each of said tread elements of the tractor so as to rise and fall therewith; cable actuating means; a cable' extending from said cabie actuating means to at least one of said supporting members; means for guiding said cable from one to the other of said supporting-means and also to said ground engaging member whereby movement ofsaid cable will accomplish movement of said ground engaging member, said guide means having a spreader member extending from one of said supporting members to the other, and guide members for the cable secured at the opposite ends of the spreader member so that a portion of the cable will be carried along said spreader member from one of said supporting members to the other; and means for connecting the cable to said ground engaging member so that movement oi!- said cable will result in movement oi said ground engaging member.

FRANK P. 

